Histological evaluation of lung fibrosis at 16 weeks post -XRT. Mice on control diet (0% FLC) were exposed to a single fraction thoracic X-ray radiation therapy (13.5 Gy). Following XRT exposure, mouse cohorts (n=15) were switched to 10% FLC or 20% FLC diets that were initiated 24, 48, or 72 hours post radiation exposure while control-fed mouse cohorts remained on 0% FLC diet throughout the course of the study. Lungs were harvested at 16 weeks post-XRT and processed for Trichrome staining to evaluate collagen deposition and fibrosis. Representative lung sections stained with Trichrome are shown on Panels A-C: representing 0% FLC, Panels D-F: representing 10% FLC and Panels G-I: representing 20% FLC. (Magnification 400X).